Minor hardening of person view aspect in sample app
Redo person deletion on person view controller

Includes localization reorganization and additions.
Harden and simplify account nation slug prompt alert
Don't lazy-init account manager in sample app
Fix zombie selected state on person cells
Add UIKit extension for layout constraint macros

Only includes centering attributes.
Fix autorotate support for not-ready label in sample app
Expose account authenticator for convenience
Introduce class-specific log level configuration and integration

Only includes client and authenticator classes.
Merge branch 'master' into peng/add-account-switching

Conflicts:
	NBClientExample/NBClientExample/Classes/NBPeopleViewController.m
Clean up sample app data sources

Remove, refactor, and clarify as needed.
Add support for persisting same-nation accounts

This requires updating the entire accounts and
auth aspect:

- The authenticator needs to allow its credential
identifier to be mutable.

- The account needs to be able to customize the
credential identifier to also contain the user
name and id, so it will be saving the credential
manually and turning off its authenticator's
auto-save.

- The accounts manager needs include the user id
when persisting and restoring accounts. It also
should prevent activating duplicates and try to
always keep an account active.

Includes minor refactoring and reorganization.
Add support for account persistence for n managers

This requires a dynamic yet nonrandom identifier.
The default implementation, using the delegate's
class name, only works partially (as noted). But
it also requires the manager's delegate be a
required property, which consequently updates a
lot of code. Flags and options have also been
changed to delegate methods as needed.

The real solution is to allow the delegate to
customize the identifier and ensure the
user-defaults key's uniqueness.
Persist accounts more frequently
Auto-sign-out when adding another same-nation account

Pass the return-to url as a param for the nation's
logout endpoint, so Safari first signs out before
re-authorizing. This ensures the user signs in
again and that the authorizing account is correct.

Signout only happens upon request on a 1-1 basis.

Also note the url generation workarounds for Safari.